1. Field of the Invention
The present invention relates to a bridge system for connecting a high-speed Power Line Communication (PLC) network and Ethernet, and more particularly, to a bridge system for connecting the high-speed PLC network and Ethernet which can provide Quality of Service (QoS) by identifying a flow of each service when a bridge system performs a bridging operation to connect the high-speed PLC network which provides the QoS and the Ethernet which does not provide the QoS.
2. Description of the Related Art
In a home network field, diverse network technologies have been introduced to provide a multimedia service as well as a home automation service by connecting diverse electronic appliances used at home. A network technology for the home network is divided into a wired network technology and a wireless network technology. The wired network technology includes a method using a telephone line, a method using a power line and a method using Ethernet. The wireless network technology includes a method using Local Area Network (LAN) and a method using Bluetooth.
The Power Line Communication (PLC) technology is a technology for transmitting/receiving data and providing an Internet service using on the power line installed at home. The PLC technology has advantages of low cost and less effort required for laying additional communication infrastructure. Recently, HomePlug Powerline Alliance defines HomePlug AV (HPAV) to provide a high quality, a multi-stream and a home entertainment environment on the power line of home as a next generation standard technology. The HPAV adopts an enhanced physical layer and MAC layer technologies for providing a PLC network of 200 Mbps level. In particular, the MAC layer also provides Time Division Multiple Access (TDMA) method securing Quality of Service (QoS) such as reservation of a bandwidth, high reliability and the strict control of a delay time and Jitter as well as a Carrier Sense Multiple Access (CSMA) method. As described above, the high-speed PLC technology is expected to be used as a backbone network for providing the QoS in the home network field.
Meanwhile, Ethernet is the most broadly set up LAN technology. The Ethernet uses the CSMA method, in which multiple users share one circuit and a 100 Mbps transmission speed can be provided. There is an advantage that the Ethernet method provides an inexpensive high-speed network. However, the Ethernet generally does not provide any function for reliability of data or the QoS. When additional tag information is added to an Ethernet frame to provide the QoS function in the Ethernet as suggested in IEEE 802.1p/q, a maximum of 8 service classes can be defined according to priority and the differentiated QoS can be provided in the Ethernet. However, there is a disadvantage that overhead occurs for additional information in the Ethernet frame to provide priority information and it is required to set up tag information according to service classes in all devices.
A bridge apparatus for connecting the PLC network and the Ethernet is required to perform data communication between an electronic appliance connected to the PLC network and an electronic appliance connected to the Ethernet.
FIG. 1 is a block diagram illustrating a bridge apparatus for connecting a high-speed PLC network and the Ethernet.
As shown in FIG. 1, a bridge apparatus 30 for connecting a typical Ethernet and a PLC network includes a PLC device driver 32 and an Ethernet device driver 33. The PLC device driver 32 transmits and receives data through a PLC network 10. The Ethernet device driver 33 transmits and receives data through an Ethernet 20. The bridge apparatus 30 communicates with a PLC device 11 and an Ethernet device 21. The PLC device 11 includes an application 12 and a PLC device driver 13, and is connected to the PLC network 10. The Ethernet device 21 includes an application 22 and an Ethernet device driver 23, and is connected to the Ethernet 20. Also, the bridge apparatus 30 performs a bridging operation that determines a destination network according to a second layer address of a destination and transforming a frame transmitted from the Ethernet device 21 or the PLC device 11 into a frame format corresponding to a destination network through a bridge function unit 31.
As described above, the high-speed PLC network can provide the QoS function, but Ethernet does not provide the QoS function. Therefore, when an Ethernet traffic is transmitted through the PLC network, the QoS function provided by the PLC network is not used. In addition, since the Ethernet does not secure the QoS in case that a QoS traffic securing the QoS in the high-speed PLC network is transmitted through the Ethernet, the QoS is not provided. Therefore, there is a demand for a method for providing the QoS by removing the heterogeneity of QoS between two networks except the bridging function in the bridge system for connecting the high-speed PLC network, which provides the QoS and the Ethernet, which does not provide the QoS.